3-alkoxy-1-propanols have a hydroxyl group in the molecule and can be used as materials for various reactions such as esterification reaction, etherification reaction and halogenation reaction, and are therefore important compounds suited for use as materials for many useful compounds, especially intermediates for medicines and agrochemicals, silane coupling agents and polyester modifiers. Also 3-alkoxy-1-propanols are useful compounds because 1,3-propanediol as a material of polytrimethylene terephthalate, which has become of major interest recently, can be derived therefrom when the alkoxy ether moiety is hydrolyzed.
Japanese Unexamined Patent Publication (Kokai) No. 10-306,050 discloses, as a method for producing 3-alkoxy-1-propanol, a method for producing 3-alkoxy-1-propanol, which comprises hydrogenating 3-alkoxy-1-propanal produced by reacting an alcohol with acrolein.
However, this method had such a problem that 3-alkoxy-1-propanal as an intermediate product and acrolein as a material may cause a secondary reaction because of good reactivity to produce a large amount of by-products, and also the production process requires two steps, resulting in a complicated process.
Japanese Unexamined Patent Publication (Kokai) No. 8-113,546 discloses a method for producing 3-alkoxy-1-propanol, which comprises using an alkoxide of an alkali metal, and a halide. However, this method also had such a problem that the halide and the alkoxide of the alkali metal used in the reaction must be separately produced, and thus the process requires at least two steps, resulting in high cost for industrial production.
Japanese Unexamined Patent Publication (Kokai) No. 13-247,503 discloses, as a method for solving a problem that the production process requires a lot of steps, a method for producing 3-alkoxy-1-propanol from an alcohol and allyl alcohols in a single step.
This method is an excellent method in that 3-alkoxy-1-propanol can be produced in a single step, however, it is not suited for industrial production because of low catalytic activity.
As described above, there has never been proposed a method for producing 3-alkoxy-1-propanol in a first step in the reaction yield suited for industrial production.
Background associated with 1,3-propanediol as one of derivatives of the above-mentioned 3-alkoxy-1-propanol will now be described.
There has been developed a low-cost method for producing 1,3-propanediol, namely, compounds which are in great latent demand for materials of synthetic resins, especially materials of polyester fibers, using a chemical method or a biological method.
As a chemical method for producing 1,3-propanediol, for example, there have conventionally been known a method for producing 1,3-propanediol, which comprises synthesizing 3-hydroxypropionaldehyde (hereinafter abbreviated to “3-HPA”) by the hydration reaction of acrolein, followed by the hydrogenation reaction (Japanese Unexamined Patent Publication (Kokai) No. 10-212,253) and a method for producing 1,3-propanediol, which comprises synthesizing 3-HPA by the hydroformylation reaction of ethylene oxide, followed by the hydrogenation reaction (Kohyo (National Publication of Translated Version) No. 11-515021).
These conventional methods have such a problem that 1,3-propandiol is produced by finally hydrogenating 3-HPA, and thus the unreacted 3-HPA may be remained in 1,3-propanediol. Also there is such a problem that odor and discoloration are caused when a polyester is synthesized by using 1,3-propanediol containing a carbonyl compound such as 3-HPA.
Therefore, it is preferred that the resulting product 1,3-propanediol does not contain a carbonyl compound such as 3-HPA. Japanese Unexamined Patent Publication (Kokai) No. 6-40,973 and Kohyo (National Publication of Translated Version) No. 11-509,828 disclose that it is difficult to remove the carbonyl compound by a conventional purification method such as distillation.
To obtain 1,3-propanediol having a low content of the carbonyl compound including 3-HPA, Japanese Unexamined Patent Publication (Kokai) No. 6-40,973 discloses a method of carrying out the hydrogenation reaction of 3-HPA in two steps and Kohyo (National Publication of Translated Version) No. 11-509,828 discloses a method of removing a carbonyl compound by reacting with an alkali. However, according to both methods, it is difficult to attain 100% of a conversion ratio of 3-HPA, and the remained carbonyl compound must be removed, and this increases a burden to the process, resulting in high production cost.
To solve these problems, a chemical method for producing 1,3-propanediol without using 3-HPA as a material has been studied. The method includes a method of hydrolyzing an ether alcohol compound, namely, 3-alkoxy-1-propanol.
Japanese Unexamined Patent Publication (Kokai) No. 6-157,378 discloses, as a reaction method for producing a diol compound by hydrolyzing an ether alcohol compound such as 3-alkoxy-1-propanol, a method of hydrolyzing 4-oxa-1,7-heptanediol in the presence of a catalyst such as ion-exchange resin or zeolite to obtain 1,3-propanediol.
However, in this publication, a substrate used for hydrolysis is limited to 4-oxa-1,7-heptanediol and it is not disclosed whether or not this method can be applied to the ether alcohol compound. This method had such a problem that high temperature of 200° C. or higher is required for efficient proceeding of the hydrolysis reaction, resulting in high energy cost for industrial production.
Similarly, Japanese Unexamined Patent Publication (Kokai) No. 11-209,318 discloses a method of hydrolyzing an ether compound in the presence of an acid catalyst to obtain an alcohol.
However, this method described in the publication has such a problem that a large amount of by-products other than the alcohol are produced, although a high conversion ratio of the ether compound is attained during the reaction. Also it is difficult to use the method for industrial purposes because of a low selectivity coefficient. Similarly to the above-mentioned method, this method had such a problem that high temperature of 200° C. or higher is required for efficient proceeding of the hydrolysis reaction, resulting in high cost for industrial production.
European Patent No. 1,201,633 also discloses a method of hydrolyzing an ether compound in the presence of an acid catalyst to obtain an alcohol.
However, the method described in the publication also had such a problem that the reaction temperature of 250° C. or higher is required to attain high reaction yield, resulting in high energy cost for industrial production. In this publication, a substrate used for hydrolysis is limited to 4-oxa-1,7-heptanediol and it is not disclosed whether or not this method can be applied to the ether alcohol compound.
As described above, there has never been proposed a method for efficiently producing the objective 1,3-propanediol with low energy by hydrolyzing an ether alcohol compound such as 3-alkoxy-1-propanol.
Patent Document 1: Japanese Unexamined Patent Publication (Kokai) No. 10-306,050
Patent Document 2: Japanese Unexamined Patent Publication (Kokai) No. 13-247,503
Patent Document 3: Japanese Unexamined Patent Publication (Kokai) No. 10-212253
Patent Document 4: Kohyo (National Publication of Translated Version) No. 11-515,021
Patent Document 5: Japanese Unexamined Patent Publication (Kokai) No. 6-40973
Patent Document 6: Kohyo (National Publication of Translated Version) No. 11-509,828
Patent Document 7: Japanese Unexamined Patent Publication (Kokai) No. 6-157,378
Patent Document 8: Japanese Unexamined Patent Publication (Kokai) No. 11-209318
Patent Document 9: European Patent No. 1,201,633